1. Field of the Invention
The present invention relates to a semiconductor probe with a resistive tip and a method of fabricating the same, and more particularly, to a semiconductor probe having a metal shield that exposes a resistive region of a resistive tip, and a method of fabricating the semiconductor probe.
2. Description of the Related Art
As compact products such as mobile communication terminals and pocket PCs have become more popular, the demand for highly-integrated nonvolatile micro recording media has increased. It is not easy to miniaturize existing hard disks or to highly integrate flash memories. Therefore, information storage devices using a scanning probe have been studied as an alternative.
Probes are used in various scanning probe microscopy (SPM) techniques. For example, probes are used for a scanning tunneling microscope (STM) that detects a current produced when a voltage is applied between a probe and a sample to reproduce information; an atomic force microscope (AFM) that uses an atomic force developed between a probe and a sample; a magnetic force microscope (MFM) that uses an interactive force developed between a magnetic field produced by a sample and a magnetized probe; a scanning near-field optical microscope (SNOM) that overcomes a resolution limitation caused by the wavelength of visible light; and an electrostatic force microscope (EFM) that uses an electrostatic force developed between a sample and a probe.
In order to record and reproduce information at high speed and high density using such SPM techniques, a surface charge in a small area of several tens of nanometers in diameter should be detected. Also, cantilevers should be in the form of an array to increase recording and reproduction speeds.
FIG. 1 is a schematic cross-sectional view of a resistive tip of a semiconductor probe and a storage medium, disclosed in International Patent Publication No. WO 03/096409. The semiconductor probe is vertically formed on a cantilever to protrude from the cantilever. An array of the semiconductor probes can be fabricated, and each of the semiconductor probes can be fabricated to have a diameter of tens of nanometers.
Referring to FIG. 1, a tip 50 of the semiconductor probe includes a body 58 doped with a first impurity, a resistive region 56 formed at the peak of the tip 50 and lightly doped with a second impurity, and first and second semiconductor electrode regions 52 and 54 formed on sloped sides of the tip 50 with the resistive region 56 therebetween and heavily doped with the second impurity. Here, if the first impurity is a p-type impurity, the second impurity is an n-type impurity, and if the first impurity is an n-type impurity, the second impurity is a p-type impurity.
The quantity of surface charge 57 of a recording medium 53 affects the intensity of an electric field. A change in the intensity of the electric field causes a change in the resistance of the resistive region 56. The polarity and intensity of the surface charge 57 can be detected from a variation in the resistance of the resistive region 56.
Although a depletion region 68 of the resistive tip 50 does not extend to the first and second semiconductor electrode regions 52 and 54, the volume of the resistive region 56 is reduced due to the depletion region 68, which acts as a non-conductor. Consequently, the resistance of the resistive region 56 changes, such that the polarity and intensity of the surface charge 57 can be detected.
However, in a conventional semiconductor probe with the resistive tip 50, the semiconductor electrode regions 52 and 54 formed on the sloped sides of the resistive tip 50 are affected by the surface charge 57, thereby degrading the spatial resolution of the resistive region 56.